Steam-turbine construction



Dec. 29,1925- 1,568,034

F. LOSEL STEAM TURBINE CONSTRUCTION Filed August 26, 1924 INVENTORATTORNEY Patented Dec. 29, 1925.

UNITED STATES raANz LosnL, or'BRUuN, czaonosnovaxm.

STEAM-TURBINE CONSTRUCTION.

Application filed. August 2-6, M324r Serial No. 734,354.

zen of Czechoslovakia, residing at Brunn,

Czechoslovakia, have invented certain new and useful Improvements lllSteam-Turbine 7 Construction, of which the following is a lpecification.

This invention relates to turbine constructions of the elastic fluidtype.

The object of the invention, generally stated, is a turbine constructionin whlch the leakage losses are substantially reduced as compared withprior constructions and which is of durable character and may beeconomically manufactured. I effect this purpose by a novel combinedrotor and enclosing casing construction having a reduced leakageclearance space andperm1tting the use of comparatively thin rotor bladecovering rings without impairing the structural strength. a 3

For better understanding of the invention, reference may be had to theaccompanying'drawings wherein Fig. 1 is a partial sectional yiewthrougha turbine embodying my inventlon, and

Fig. 2 is a similar View illustrating a modified construction.

Referring to Fig. 1, I/have indlcated a rotating bucket blade or elementa of a rotating disc or wheel having therearound a shrouding or coveringring I). A portlon of the enclosing casing or carrier body for the guideblades is indicated at (Z, and the stationary guide nozzles on oppositesides of the rotating bucket a are illustrated d1agrammatically andindicated by the letter g. The shrouding or cover ring I) is indicatedof very small depth or thickness, and is connected with the blades orand secured 111 place by rivets of a character indicated by the letter0, the latter being substantially centrally disposed between theopposite edges of the ring- The ring 6 is of the thin character andconstruction indicated to minimize the centrifugal forces and to re duoethe thrust losses due to the thrust of the steam upon the enteringperipheral edge of the ring Z2, and in order topern it only a partialcounter sinking of the rlvet heads 0 into the outer surface of the thinring 6 and to avoid the weakening of the structure due to full countersinking, I form the interior of the casing or part 03 with ,an interiorenclosing surface so'a's to form a rely smal d araae 9 he l t e ie therivets o and in the front side of the ring but a larger clearance f forthe remainder or trailing portion of the width of the blades (1, theclearance f being of sufficient depth to safely clear the protrudingrivets c which secure the ring I) in position. The clearance c is verysmall and is just large enough to clear the shrouding ring 6 under allconditionsof operation, whereby the leakage of steam through therotating canals, about the periphery of the ring Z) is reduced to apractical minimum. Moreover, due to the thinness and small depth of theenclosing ring 5, the losses from the thrust and impingement of thesteam upon the axially disposed edge thereof is reduced to a minimum,

while the ring 6 is secured firmly in position by the non or partlycountersunk rivets 0 whose heads are cleared by the machined out portionof the casing part d indicated by the clearance f. In the embodiment ofmy invention exhibited in Fig. 1 the ring 6 is indicated ofsubstantially equal depth throughout its width and the clearances e andf may be provided by machining the the interior enclosing surface wallof the enclosing member or casing d at two different diameters indicatedby D and D the diameter D being sufficiently larger than the diameter .Dto clear the outwardly proecting or protruding rivet heads 0 under allconditions of operation.

In the example of my invention exhibited in Fig. 2 the trailing part ofthe ring 6 is of uniform depth or thickness from the right to apointjust past the protruding rivet heads 0, but from that pointto theleft hand or leading edge the ring 7) is made of increasing depth at anangle 00 to the horizontal, and the casing d is conically machined offat an angle to the horizontal corresponding to the angle :20, so as toform the clearance e of very small depth so as to reduce the tendency ofthe elastic fluid to leak therethrough. A clearance f to the right isindicated of the general character shown in Fig. l for clearing therivet heads 0. Arrow 2' indicates the direction of the steam trying ortending to escape up past the bucket a the flow of the working steam,tends to counteract and compensate for the tendency of the steam to flowin the opposite direction indicated by the arrow I. The clearance orleakage loss, therefore, is reduced both because of the small depth ofthe clearance 6,.

means of the wedge or conical shaped construction of the front edge ofthe ring 6 the leakage loss furtherreduced by the counter pumping orsuction effect within the clearance e opposite to the flow oftheworlring fluid. Moreover, theconstruction is of simple character andmay be cheaply and economically manufactured.

Having thus described my invention, whatI claim as new and desire tosecure by Letters Patent is:

1. A steam turbineconstruction compri ing a rotating blade element witha cover or shrouding ring around the. periphery therc-- of which isanchored thereto by means of securing devices projectingabove the outersurface of the ring and an enclosing casing or part forming with saidring radial clear ances of unequal depth onopposite sides of theprotruding securing ,devices, the clearance of the lesser depth being:relatively shallow but of considerable; lengthbetween the leading orenteringedgeand said protruding securing devices and the otherclear-1ance being of suflicient depth to clear; said protruding securingdevices and extending to the otl1er edge ofsaid ring.

2. In a turbine ofthe axial flow ,type, a

rotating blade ielementuhaving a shrouding enclosingring passing aroundtheperiphery there-of with anchoring rivets securing said ring to therotating element atflpoints re moved from the opposite edges thereof;and

having heads protruding above the outer. surface thereof and an enclosng cas ng or part for said rotating clement forming with said shroudlngring .a radial clearance on the trailing edge of the rlngof sufiiclentdepth to clear the protruding rivet heads,

terior of theta-Sing is formed of differentdi-..

ameters to form the unequal clearances on the opposite sides of the headring.

4. In a steam turbine of the axial flow type, rotor blades, a head ringconnected with said rotor blades and having a portion wedge-shaped, insection with its inclined surface tapering inwardly from the adjacentedge of the ring, and an enclosing stationary part having a conicalinterior portion shaped to form a relatively small clearance with saidhead ring.

5. In a steam turbine a rotating blade element having a cover orshrouding ring secured thereto by slightly protruding attaching devicesat points removed from the opposite edges of the ring and a turbinecasing or part enclosing the ring and forming therewith a clearance. onthe trailingv side of the ring of sufiicient depthto clear theprotruding parts of the securing devices.

and said ring and easing being formed with a clearance of smaller depth,on the leading side of the ring and. outwardly inclined froma pointadjacent the protruding securing devices for the purpose set forth.

(S. In a steam turbine, acombined rotat- .the outer peripheryof saidblade element va clearance parallel to theaxis and extending over partofthe blade element .width and an inclined clearance of smaller depth.for the remainder of the width. 1.

. S. In a turbine of the axial flow type, rotor blades, a head ringconnected, therewith by means including riretheads engaging the outersurface of the head ring, and a rotor enclosing structure forming withthe head. ring a relatively shallow and relatively edges,

long clearance between .the edgeof the head ring and the rivetheads andbeyond said shallow and relatively long clearance a elearance ofsuflicient depth .to .clear the rivet. heads.

9. Ina turbine ofthe axial flow .type, rotor.. blades, a headringconnected. there.- withby means includingrivet heads en,-

gaging the outer surfaceof the head ring, and an integral rotor,enclosing partforming with the head ring a relatively shallow andrelatively long clearancebetween.one

edge of the head ring and the rivetheads and beyond said shallow. andrelatively long clearance a clearance of clear the rivet heads.

10, In an elastic fluid 1111131116, arotor,

suflicient depth to blade element with a cover at the outer peripherythereof, and a casing element construction enclosing said cover andforming threrewith a relatively small clearance axially inclinedinwardly in the direction of the steam flow for part of the width of thecover and counteracting the leakage fluid flow.

11. In an elastic fluid turbine, a rotor blade element with a cover atthe outer periphery thereof, and a casing element construction enclosingsaid cover and forming therewith a relatively narrow clearance'axiallyinclined inwardly in the direction of working fluid flow from the fluidentrance edge towards a line intermediate the edges of the cover andcounteracting the leakage fluid flow, and a somewhat larger clearance onthe outer periphery of the leaving edge of said blade element.

12. In an elastic fluid turbine, a rotor blade element having a cover atthe outer periphery thereof, and a stationary portion enclosing saidcover and forming therewith at the outer periphery thereof a relativelyshallow and long clearance axially inclined in the direction of theworking fluid flow and counteracting the leakage fluid flow,

and behind said shallow clearance a greater clearance at the leavingside of said cover.

13. In an elastic fluid turbine, a rotor blade element having a cover atthe outer periphery thereof and a stationary casing portion having atits inner surface an inwardly inclined surface part enclosing said coverand forming with the outer periphery of said cover a relatively shallowand long clearance inclined inwardly from its entrance and serving ascombined tightening meansand, during operation, compressing and pumpingmeans also, counteracting the fluid leakage at the entrance of theclearance andreducing the leakage loss between said stationary portionand rotating element.

14. In an elastic fluid turbine, a rotor blade element having a cover atthe outer periphery thereof, and a stationary portion enclosing saidcover and forming with the outer periphery thereof at the entrance sideof said-element a relatively shallow and long clearance axially inclinedinwardly in the direction of the working fluid flowto act, duringoperation, as tightening means and pumping means counteracting the fluidleakage flow, and another somewhat larger clearance at the periphery ofthe leaving side of said element.

In testimony whereof I have signed my name to this specification.

FRANZ LosEL.

